VO) --
I not know how to do this

Answer:
Square root and the power of 2 cancel each other. The answer remain 4/7
The square of a number is the number times itself. For example the square of 3 is 3x3. The square of 4 is 4x4.
The square root is just the opposite of the square. You can think of it as the "root" of the square or the number that was used to make the square.